The present invention relates to a threaded member tightening method, for example, for use in fastening the components of a pipe joint together with a nut.
Pipe joints are already known which comprise a first tubular joint member having a hexagonal flange and an externally threaded portion, a second tubular joint member disposed end to end therewith, an annular gasket interposed between the opposed end faces of the two joint members, a nut provided on the second joint member and screwed on the first joint member and a thrust bearing provided between the second joint member and the nut.
With the pipe joint, a fluid-tight connection is provided by manually tightening the nut on the first joint member first and thereafter tightening up the nut with a tool with the hexagonal flange of the first joint member held with another tool. To tighten up the nut suitably, a mark is made on each of the first joint member and the nut after the nut has been manually tightened, and the nut is then turned through a required angle with reference to the marks. Alternatively, the nut is turned with a torque wrench serving as the tightening tool until a required torque value is obtained to ensure tightening.
The conventional methods of tightening the pipe joint require two tools, i.e., a tool for holding the first tubular joint member, and another tool for tightening the nut, and therefore have the problem of necessitating a cumbersome tightening procedure.
It is also cumbersome to make a mark on each of the first tubular joint member and the nut which is manually tightened and to turn the nut through the required angle with reference to the marks.
While the worker is likely to forget to install the gasket or thrust bearing when assembling the pipe joint, the conventional methods described are unable to indicate the absence of the gasket or thrust bearing, giving rise to the problem of a leak from the joint portion of piping due to improper tightening.